Extra air valve for internal-combustion engines



Dec. 7 1926. 1,609,292

R. E. BURCH EXTRA AIR VALVE FOR INTERNAL COMBUSTION ENGINES Filed March5, 1926 flfforn g.

Patented Dec. 7,1926.

UNITED STATES PATENT err-ice.

EXTRA AIR VALVE FOB INTERNAL-COMBUSTION ENGINES.

-Application filed March 5, 1926, Serial No. 92,406, and. in GreatBritain March 13, 1925.

This invention relates to an improvement in ,or modification of theinvention claimed in the specification of my Patent No. 1,553,668 ofSeptember 15, 1925, for enabling the admission of extra air to theintake of an internal-combustion engine (such for example as that of amotor car to be regulated automatically as require in accordance withthe advance or retardation of the ignition. The arran ement described inthe specification referre to comprises an arm upon the ignition-controlrod, and a lever constantly tending under spring-action to open theextra air admission valve; the arrangement, relative proportions andpaths of said arm and lever being such that whereas no extra air isadmitted so long as the ignition remains at zero, nor does any admissionof extra air take place during the advance of the point of ignition fromzero to half advance, extra air is admitted in a progressivelyincreasing proportion from nil to a maximum in accordance with thegradual advance of the point of ignition from half advance to normalfull advance, whilst such maximum admission of extra air is maintainedduring any further advance of the ignition to its earliest point, andconversely as the ignition is retarded.

The' present invention, while directed to .secure the results justmentioned, has for i its immediate object to enable spring-action to bedispensed with for the purpose of actuating the extra air admissionvalve, and to render positive the connection between the arm on theignition-control rod and the lever whereby said valve is opened andclosed, so that accidental reversal of the position of the movableelement of the valve cannot result from jarring, vibration, or otherextraneous force to which it may be subjected.

According to the present invention the arm on the ignition-control rod,during that middle portion of its totalmovement which is comprisedbetween the positions corresponding respectively 'with half advance andnormal full advance, causes by positive mechanical action the leverwhich actuates the displaceable element of the extra air admission valveto move from the position corresponding with full closure to thatcorresponding with full opening of the valve or vice versa (inaccordance with the direction of the motion) and during those twoextreme portions. of its total movement which are comprised between thepositions corresponding, on the one hand with half advance and zeroadvance, and on the other hand with normal full advance and fullyadvanced ignition, as the case may be, said arm prevents, also bypositive mechanical action, reverse movement of said lever from thefully open or fully closed position, to which ever of such positionsthat lever has last been brought. For this purpose the lever whereby thecontrol of the valve is effected may be in the form of a camadapted toimpart motion to the displaceable element of the valve and engaged bythe arm upon the ignition-control rod, while, as in the exampleillustrated and described in my Patent No. 1,553,668, said lever and armmay be movable angularly about axes substantially parallel with oneanother.

One form of the invention is illustrated by way of example in theaccompanyingdrawings as applied to an extraair admission v'alveconstituted by a rotary plug tap. Figure 1 shows the-improvement in sideelevation and Figure 2 is an end elevation.

In the example illustrated, the valve-plug is to be understood aspassing through an arc of substantially 90 degrees in moving from thefully closed to the fully open position or vice versa; whilst theignition-control rod, whereof the axis is substantially parallel to thatof the valve-plug, is to be understood as having a total normal angularmovement of substantially 90 degrees between the positions correspondingrespectively with zero advance and fully advanced ignition, this totalangle being made up of three substantially equal arcs whereof the middlearc is comprised between the positions corresponding with half ignitionand normal full ignition, the one extreme arc is compirsed between thepositions corresponding with half advance and zero advance, and theother extreme arc is comprised between the positions corresponding withnormal full advance and fully advanced ignition.

Referring to the drawings, a is the body of a rotary plug-tap serving asthe extra air admission valve of an internal-combustion engine, the axisof the rotary plug 1) of this valve extending substantially parallel tothe axis of the rotary ignition-control rod 0, which rod has fast uponit a radial arm d carrying a crank-pin e. Angular movement. of the arm(1 through its total normal range has for efi'ect to carry the'crank-pin e through an arc of 90 degrees,

that-is to say from the position w which corresponds to the fullestadvance of 1gn1t1on, through an arc of 30 degrees to the position a:which corresponds to normal full advance, thence through an arc of 30degrees to the position 3 which corresponds to half advance, and thencethrough an arc of 30 degrees to the position a which corresponds to zeroposition, and vice versa.

The crank-pin e enegages a bifurcated cam-lever 7 fast upon the rotaryplug b and presenting between its limbs g, g, towards the axls of theplug, a parallel-sided radial cam-slot h of such length as to cooperatepositively with the crank-pin 0 during movement of the latter in eitherdirection through its arc of 30 degrees between the positions at and 3between which two positions the movement of the crankpin e causes thelever g to move in a corresponding direction through its total are of 90degrees between the positions corresponding to complete opening andcomplete closure of the valve, these two extreme angular positions ofthe valve-plug I; being preferably determined by stops, such as y", 9'for example.

Beyond that end of the cam-slot k whichis remote from the axis of thevalvelug b, the limbs g, g of the bifurcated ever f are extended as atk, these extensions being outwardly curved in opposite directionssymmetrically and that limb-extensions 70' or k which, ac cording as thecrank-pin e occupies the position as or the position 3 is the moreremote from the axis of the control-rod a, being curved concentricallywith said axis. The result is that during movement of the crank-pin ebetween the positions :2: and w, or between the positions 1 and e, notonly is no movement imparted by the crank-pin to the lever f, but thelatter i prevented positively from moving reversely so as to close thevalve when once opened or to open it when once closed.

In order to afford sco e for adjustment, the curved portions k, 2 of thelimbs of the bifurcated lever f are preferably made of such length as toextend, as indicated, beyond the position w or z of the crank-pin 0 whenthe lever f is in the correspondin position, and for the sake of greaterstrengt the extremities of these limbs may, if desired, be united by across-bar m as indicated in Figure 1. Moreover, in order to allow ofadjustment of the entire lever f radially of the axis'of the valve-plugb, the lever may be slotted as at n to engage over a squared portion ofthe plug 6, the adjustment being secured by means of a nut 0 upon thethreaded extremit of the plug.

The cran -pin a, which is preferably provided with an antifrictionroller, is ad ustable radially of the axis of the ignitioncontrol rod 0,for which'purpose the crankitself is prefera pin may be constituted by ashouldered stud aving a reduced shank-portion which fits in a radialslot 1) in the arm d and is secured therein by means of a nut 1- on thethreaded extremit of the shank. The arm d hly adjustable angularly aboutthe axis of the rod 0.

' 1. In an internal combustion engine, means for controlling theadmission of extra air to the intake in accordance with the advance ofthe point of ignition, comprising a valve for regulating such admission,a manually-operable rod for controlling'the advance of the ignition, alevel for actuating said valve, and an arm on said ignition-control rodadapted to maintain constant engagement with said lever for positivelyholding the latter in predetermined positions and moving it in openingand closing said valve, the arrangement being such that (a) all thosepositions of said arm which denote progressive advance of the point ofignition from zero advance to half advance correspond with that positionof said lever which denotes full closure of the valve; that (b) thosepositions of said arm which successively denote progressive advances ofthe point of ignition from half advance to normal full advance,correspond with progressive movements of said lever from the positiondenoting full closure to the position denoting full opening of thevalve; and that (c) all those positions of said arm which denoteprogressive advances of the point of ignition from normal full ad- Vanceto maximum advance, correspond with that position of said levervwhichde-. notes full opening of the valve.

2. In an internal combustion engine as claimed in claim 1, means forcontrolling the admission of extra air to the intake, wherein the lever,for actuating the air-admission valve is bifurcated in a plane parallelto the plane of movement of the arm on the ignition-control rod, saidarm being cranked to engage the respective limbs of the leveralternately in accordance with the direction of movement of the arm andlever.

engagement by said crank-pin, while beyondthat end of the-slot which isremote from said axis the limbs of the lever are outwardly curvedsymmetrically in opposite directions about centres which respectivelycoincide with the axis of the ignition-control rod when the lever is inits extreme angular positions.

A. For use in an internal-combustion engine, an extra air admissionvalve having a rotary spindle, means for preventing angular movement ofsaid spindle beyond the positions corresponding respectively with the.

fully closed and fully open positions of the valve, an ignition-controlrod whereof the axis extends parallel with that of the valvespindle, anarm on the ignition-control rod, a cam-lever on the valve-spindle havingtwo limbs extending in the plane of rotation thereof, and a crank pin onsaid arm adapted to engage the mutually-opposed inner.

edges of said limbs; said inner edges, throughout that portion of theirlength which is nearest the valve-spindle, being parallel to one anotherat opposite sides of a radius from the axis of the valve-spindle and atsuch distance apart as just to admit the crank-pin between them, and,throughout the remainder of their length, being concavely curvedrespectively to radii struck from the axis of the ignition-control rodwhen the cam-lever occupies its corresponding limit positions,substantially as described.

' ROBERT ERNEST BURCH.

